How to explain Dom3 to a 5 year old?

[Chazar]

How can you explain Dom3 to a 5 year old child?

Are there any very simple turn-based children's games that feature Wizards & Dragons fighting?

The story:
My 5 year old son caught me off guard while I was watching half a dozen Tarrasques obliterate my monkey PD, trapping my pretender inside a castle. He watched struck by awe (Bug-Report: Tarrasques don't show the Awe-Attribute that they must clearly have ), and asked me what this game was all about.

So I shortly replied that these "dragons" attacked me and that I was just pondering how to defeat them, but that it was horribly complicated. However, my son continued to ask questions, and I made the mistake to mumble something about "using my wizards to bewitch the dragons". Well, I hoped that he would drop the issue after another day or two, but Wizards & Dragons apparently have a certain appeal for 5 year olds, so he keeps asking me about this strange game he does not understand on and on.

Now delving deeper into Dom3 will only make it worse. So I am looking for other ways to satisfy his curiosity.

So are there any remotely similar games featuring Wizards & Dragons (for PC, Android or Table-Top) that are suitable for a 5 year old that cannot read, and can only read and compare numbers up to 19?

It should also be turn-based, because I think he has a problem understanding the concept. He asked me to try this and that tactic to fight the dragons,* but I said that I would take another day to see the results, since my opponents need to make their moves too Most games he plays are action oriented, e.g. AngryBirds, where results are immediate. However, he does play turn-based boardgames, so I think that the concept of planning a turn is difficult, but possible to grasp for him. The problem surely lies in the scale that he could not understand (days between turns).

(* "Get some knights with lances!" "The dragons are surrounded by poisonous fumes, so we cannot get close." "Then shot them with arrows!" "The dragons have thick scales, so the arrows won't harm them." ... - I cannot remember what he replied, but he came up with several suggestions after each of my responses... )